Letty groaned as the alarm clock sounded. A textbook was still open next to her on the bed. With eyes half-open, she dressed in her waitressing uniform. Early customers didn't normally tip very well, but the diner was the only place she could get in a quick shift before classes started. At least she'd be off her feet for a while at school before she had to go to her evening job at the factory. It was all Letty could do to stay awake after four hours there to study a bit before bed. Then she'd be up to do it all again the next day. What is the best inference you can make about Letty?